NU2318 bearing: complete specifications & equivalents
The NU2318 is a ISO 15 radial bearing sized 90 x 190 x 64 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 90 mm |
| Outer diameter D | 190 mm |
| Width B | 64 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 360 kN |
| Basic static load rating C0 | 395 kN |
| Fatigue load limit Pu | 43.5 kN |
| Limiting speed (mechanical) | 3200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 7790 g |
| Manufacturer designation | NTN NU2318 |
| Standard | ISO 15 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203E |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.
Dimensions in inches & NU2300-series range
| Bore d | 3.543 in |
|---|---|
| Outer diameter D | 7.48 in |
| Width B | 2.52 in |
| ISO bore code | 18 |
| Radial section height (D−d)/2 | 50 mm |
| Smallest bore in NU2300-series | 20 mm |
| Largest outer diameter in NU2300-series | 750 mm |
| Width range across NU2300-series | 21–224 mm |
| Bore position in NU2300-series (smallest first) | 15 of 35 |
| Bore above smallest NU2300-series size | 70 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU2318-ECP | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 90×190×64 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the NU2318 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, NU2318 appears as a 90 mm bore single-row cylindrical roller bearing (360 kN C / 395 kN C0) with a pressed sheet-steel cage, listed to the ISO 15 boundary plan. The leading NU defines the rib arrangement (outer ring ribbed, inner ring ribless); the dimension-series digits and the two-digit bore code resolve to 90 mm, with 190 mm OD and 64 mm width from the ISO 15 general plan. the bare number is the standard-capacity open execution with the normal pressed-steel cage; quote the full NU2318 designation when purchasing. Equivalent-load planning treats NU2318 as a pure radial bearing: keep P below 360 kN at the required L10, and let a paired angular-contact or thrust part carry any sustained axial component. Housing and shaft fillets must clear the ring chamfers of NU2318; an oversized radius locks the ring on its face and tilts the 64 mm-wide seat.
Typical equipment & failure modes
Common applications
- rolling-mill auxiliary drive shafts
- crusher and vibrating-screen drive shafts
- marine gearbox and deck-machinery shafts
- large electric-motor and generator rotors
Known failure patterns
- roller smearing (microwelding) at start-up before the oil film builds under insufficient radial load
- pressed-steel cage pocket wear when rollers skid at light load or too-thin lubricant
- micro-pitting when the EHL film falls below the composite roughness at high specific load
- fretting corrosion on a loose rotating shaft seat
- rolling-contact fatigue after the catalogue L10 life is exceeded
Selection pitfalls — read before you substitute
- Induction-heat the 90 mm inner ring (max 120 °C) and mount it before fitting the outer ring; the ring mass makes square guidance essential — driving through the rollers brinells the 190 mm raceway.
- The 64 mm width and abutment faces must be square to the axis; a tilted spacer concentrates load across the roller set and shows as uneven raceway polish on the 90 mm inner ring.
- Do not replace NU2318 with a deep-groove ball bearing on rating alone: line contact gives 360 kN radial capacity but the bearing cannot carry the thrust duty a ball bearing can and misalignment tolerance is only 3–4 arc-minutes.
- Wide (22/23) and light (10/49) executions at 90 mm bore share bore but not OD/width; check the full NU2300 series code before substituting, because housing and shoulder geometry will not interchange.
- The 64 mm width and abutment faces must be square to the axis; a tilted spacer concentrates load across the roller set and shows as uneven raceway polish on the 90 mm inner ring.
- The 360/395 kN ratings, 43.5 kN Pu and 7790 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU2318 (standard execution); other makes sharing the ISO 15 envelope revise internal geometry without changing the order number, so keep the 2203E reference with the specification for critical drives.
Frequently asked questions
What are the dimensions and catalogue data of NU2318?
NU2318 is an NTN NU single-row cylindrical roller bearing to ISO 15: 90 mm bore, 190 mm OD and 64 mm width (3.543 × 7.48 × 2.52 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 360 kN, C0 395 kN, Pu 43.5 kN, grease limiting speed 3,200 r/min, oil 3,800 r/min, mass about 7790 g. It is open, with a pressed sheet-steel cage.
What is the difference between NU, NJ, NUP, N and NF cylindrical roller bearings?
The prefix states the rib arrangement: NU has two outer-ring ribs and a ribless inner ring (float, no axial load); NJ adds ribs for one-direction location; NUP adds a loose L-ring to locate both directions; N has two inner-ring ribs and a separable outer ring; NF has one rib per ring for one-direction guidance. NU2318 is two integral ribs on the outer ring and a ribless, separable inner ring — a non-locating bearing that lets the shaft float axially.
What do the EA, E and ＊ suffixes mean on NTN cylindrical roller bearings?
EA is NTN's high-capacity design with a pressed sheet-steel cage and optimised roller complement in the same ISO 15 envelope; E marks the high-capacity design at the larger bores; the ＊ symbol printed before the code in the NTN catalogue marks the ULTAGE new-generation specification and is not typed as part of the order number. NU2318 is supplied in the standard open execution shown in the table.
Can NU2318 take axial load and locate a shaft?
the NU design carries no axial load and floats axially on both sides. Provide axial location with an adjacent locating bearing (angular-contact, deep-groove or a paired NJ/NUP set).
What do Fw and Ew mean for NU2318?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 115 mm, Ew 165 mm. The nominal bore/OD remain 90/190 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 3,200 r/min grease / 3,800 r/min oil.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203E on 2026-10-01. Read our editorial & correction policy.